Leather-like material



Patented Nov. 10, 1936 UNITED STATES PATENT OFFICE No Drawing. Application August 8, 1934, Serial No. 739,001

9 Claim.

This invention has for its object the preparation of a new and improved material for use in the manufacture of artificial leather, gaskets, water-resistant and/or waterproof fibrous products. More specifically, it relates to the preparation of a fibrous base material, and an impregnated fibrous product, the impregnant being usually, but not always, rubbery in nature, or assimilating the very desirable features of rubber.

Artificial leather for use as loose-leaf book covers, blank check book folders, straps, pocketbooks, uppers for shoes, shoe linings, gasket stock, and so forth, is usually prepared by impregnating either a Woven textile fabric or an especially prepared fibrous matted base, and subsequently coating and/or embossing it to give it a leatherlike appearance. For some purposes the impregnant used is rubber latex, or adulterated latices; for other purposes, rubber substitutes, glueglycerine-formaldehyde compounds, redispersed old rubber suspensoids or emulsions, rubber latexglue mixtures, rubber-latex-asphalt emulsion mixtures, and similar water-resistant and/or waterproof substances are used. For many purposes, the impregnated product may be used without additional treatment.

The usual fibrous product used as a vehicle for the impregnant was, originally, a woven textile material. Subsequently, a superior product was prepared, and great economies effected, by and through the use of a fibrous bat, in place of the woven textile. Still later, steam-felted felts, known as fulled felts, came into use. Finally, paper-base fibrous products were tried, with but limited success.

After long periods of experimentation, it has been proven that the ideal fibrous base would be one having the long-fibre characteristics of a fulled felt or bat, and yet be capable of being sheeted out by means of a Fourdrinier, cylinder-machine, wet-machine, combinations of such machines, or similar water-medium felting machines.

In the preparation of fibrous sheet products, the usual procedure consists in beating rags, wood pulp, or other cellulose-containing fibres, in the presence of water, until the stock has been reduced to a smooth pulp, then refining the aqueous mass, by means of a Jordan engine, so-called, and finally, after screening out objectionable matter, sheeting out the disintegrated fibres, in the presence of water, by means of a Fourdrinier, cylinder machine, wet machine, or combinations of such sheeting machines.

In order that a smooth, uniform sheet may be prepared by the use of the aforementioned machines, the fibres of the pulpy mass are usually fairly short, the actual length varying with different fibres. For example, ground wood fibres are of the order of 3 or 4 millimeters in length, while chemically cooked may approach 6 or 7 millimeters in length. Rag fibres, derived from cotton or linen materials, may be somewhat longer, and still be suitable for the preparation of smooth, uniform sheets.

Attempts have been made to prepare pulp or fibrous products by means of the aforementioned machines, in which a proportion of the fibres in the sheet material are longer than those usually found in'the ordinary type of product made thereon. Such products, however, have not lent themselves readily for impregnation with rubber latex,

glue-glycerine-f0rmaldehyde compound, or similar saturants, and after impregnation with such saturants, have not possessed the element of strength so necessary and desirable in such products, the reason being that such fibrous sheet products consisting as they did of short fibre bases, having relatively longer fibres distributed therethrough, and in felted relation therewith, necessarily contained a preponderance of the short fibres, and a much smaller amount of the relatively longer fibres, and in addition, the relatively longer fibres were not amenable to reasonably rapid beaterhydration, nor were they in consequence readily capable, of themselves, of fibre-interlocking, in the presence of a water medium, with the relatively shorter fibres.

My present invention makes possible the preparation of a fibrous product having exceptional strength, yet highly absorbent, and which on impregnation with the various substances heretofore mentioned, results in a very strong and tough leather-like material, suitable for artificial leather purposes, gaskets, and other uses, previously noted.

My present invention contemplates the use of various fibres, of various lengths, and of animal, vegetable, and mineral origin which I have found can be used as the base of a saturation product, such fibres being blended, in the presence of water with other fibres, formed into a sheet, and serving as a vehicle for various impregnating compounds.

In the preparation of the felt, it is essential that some reasonably short fibres be present. The function of these short fibres being to facilitate the bonding together, in the presence of wa ter, and by means of a screen, of the fibres to form a sheet. In the preparation of this felt or saturation vehicle, it is desirable to have relatively long fibres present, and it is very desirable that such relatively long fibres be amenable to either entwinement around, between or by the short fibres, or by virtue of their nature, be susceptible of felting in the presence of water, through the assistance of a screen, either with other long fibres or with the short fibres.

As an illustration of the method I prefer to use in manufacturing this fibrous product, I give the following example: Cotton rags, such as shoe 4 lining trimmings, or new white cuttings, or old cotton rags are treated in such a manner as to result in fibres of varying lengths. This may be done by passing the rags through a textile picking machine, by means of which the proportion of long and short cotton fibres may be controlled. This may also be done by careful beater treatment to result in a mass containing both long and short fibres, the relative amount being controlled by proper handling 01' the beater roll. This may also be accomplished by rag-cutting pre-treatment, prior to beating, or pulping.

In using, for example, cotton rags as the raw stock for preparation of the fibrous product, it is highly desirable to control first, the relative lengths of the short and long fibres, and, second, the relative percentages by weight and volume, or number, of the long and short fibres.

The relative lengths of the short and long fibres may be governed, first, by the initial length of the fibre used, second, by the pretreatment given it, that is, textile picking, cooking, cutting, half-stocking, or beater treatment in the judicious handling of the roll. The relative percentages of the long and short fibres should be so adjusted to give the impregnated material the maximum strength, and so as to enable the saturation vehicle, or fibrous product, to be saturated without tearing, and to withstand the rigors of coating and embossing. Further, and what is highly important, is that the percentages of long and short fibre be so regulated as, in addition to running well on the sheeting machine, the proportion of short fibres be sufllcient to carry the longer fibres, in the case where non-hydratable fibres are used for the long fibre content, such as hair, wool, leather, asbestos (long), elongated ligno-cellulose fibres, such as jute, hemp, etc.; and in the case of the long hydratable fibres, such as cotton, ramie, rope stock, etc., including certain types of long but hydrated vegetableorigin fibres, the percentage of short fibres should be so regulated as to result in a soft, porous, highly absorbent material, which after impregna tion will be very strong.

We have found, by way of example, that an all-cotton felt, made from new shoe cuttings, having only 40% short fibre i. e., less than five millimeters in length, and 60% long fibre, i. e., approximately 17 millimeters in length, results in a highly absorbent, yet very strong fibrous vehicle, which after saturation with the aforementioned impregnants, is very strong, tough, and leather-like.

By means of the process herein described, I have been able to prepare fibre bases for use as vehicles for such impregnants as, rubber-bearing compounds, rubber substitutes, or rubber-simulating compounds, such as glue-glycerine or glueglycerine-formaldehyde, etc., in which the fibrous base may be composed of a body of long fibres having short fibres distributed therethrough; and by suitable choice of the fibres used, the long fibres may, and in some cases may not be, in

felted relation with the short fibres. Further, through judicious choice of the fibres used, the long fibres may be present in preponderating amount, yet not necessarily in number.

In the preparation of the base vehicle, I am not limited to any particular class of fibres. For instance, in addition to a mixture of long and short cotton fibres, I may use, in lieu thereof, short rope fibre along with long cotton fibre, or long linen fibre along with short ramie fibre, or some animal or mineral fibre in place of the long or short vegetable fibres, and subsequently impregnate with rubber compounds or rubber-like impregnants. A portion of the fibres should be of vegetable origin.

The method of associating the long and short fibres may also take different forms. For instance, I may subject the fibres to a preferential textile picker selection process; or judicial and variable mechanical cutting may be resorted to; or the heater or rod mill may be so handled as to result in the desired mixture of long and short fibres; or half-stocking may be resorted to.

In order to obtain length of fibres from normally short fibrous materials, I may so treat the stock as to result in an eventual mixture of long bundles of unravelled fibres, quite thick in comparison to the shorter, and thinner isolated fibres.

Then, too, instead of impregnating the base vehicle, I may also modify the process to provide for a mixture of long and short fibres and rubber compounds, or rubber-like compounds, to be sheeted out together, thus avoiding the subsequent saturating step.

In using the expression rubber-containing compound, I mean to designate both the use of such rubber bearing substances as rubber latex, dispersions, adulterated rubber-containing subber, mixtures of rubber latices with glue or asphalt dispersions, adulterated rubber-containing substances, and similar substances containing at least some real rubber or rubber family member, such as gutta percha, balata, pontianac, guayule, etc., and also the eventually dried product obtained therefrom.

In using the expression rubber-simulating compound, I mean to designate such substances as have been recognized as rubber substitutes, such as sulphonated or sulphurized oils, etc., together with such compounds as glue-glycerineformaldehyde, glue-glycerine-dichromate, glueglycerine, etc., rubbery compounds and also the substantially eventually dried product obtained therefrom.

The use of the expression glue-glycerinecompound is intended to cover the various glue compounds having rubber-like properties, such as glue-glycerine, glue-glycerine-formaldehyde, glue-glycerine-dichromate, and like compounds having rubber-like properties. This does not include such compounds as asphalts, waxes, and so forth, of strictly waterproof and/or meltable nature.

By the expression "relatively short fibre or "short fibre, I mean the usual length of fibre commonly used in the preparation of ordinary papers or felts. By the expression relatively long fibre or long fibre I mean fibres whose length is greater than that commonly used in the preparation of ordinary papers and water-laid materials for paper purposes, being approximately of the order hereinbefore cited. or course considerable latitude must be allowed in the actual length of fibres used due to the variations present in the commercially available raw materials.

Further, by the use of the term short fibre I mean short with respect to the usual length of fibre encountered in the textile industry, and by the use of the term long fibre I mean long with respect to the usual length of fibre encountered in the paper industry.

It is immaterial whether the fibres are new, such as cotton fibre fresh from the plant, or assumes the form of new cotton cuttings such as new shoe rags, or shoe rag cuttings, or come from old or new textile rags, or constitute a waste or old product.

All such and related variants are to be considered as within the scope and purview of my invention as defined in the appended claims.

In the appended claims the term water-laid refers to a fibrous product, the fibres of which have been sheeted out in an aqueous medium, as by means of a Fourdrinier, cylinder-machine, wet-machine, or combinations of these or similar machines.

What I therefore claim and desire to secure by Letters Patent is:

1. A leather-like material, comprising a waterlaid fibrous base, consisting of a felted mixture of relatively long and short fibres, as described, and impregnated with a rubber-containing compound, a portion of the fibres being of vegetable origin, and the shorter fibres being thin and substantially individually isolated, and at least a portion of the longer fibres being relatively thick, unravelled bundles of fibres.

2. A leather-like material, comprising a waterlaid fibrous base, consisting of a felted mixture of relatively long and short fibres, as described, and impregnated with a rubber-containing compound,

a portion of the fibres being of vegetable origin,

and the proportion of relatively longer fibres being greater than that of the relatively shorter fibres, and the shorter fibres being thin and sub stantially individually isolated, and at least a portion of the longer fibres being relatively thick, unravelled bundles of fibres.

3. A leather-like material, comprising a waterlaid fibrous base, consisting of a felted mixture of relatively long and short cotton fibres, as described, and impregnated with a rubber-containing compound, and the shorter fibres being thin and substantially individually isolated, and at least a portion of the longer fibres being relatively thick, unravelled bundles of fibres.

4. A leather-like material, comprising a waterlaid fibrous base, consisting of a'felted mixture of relatively long and short cotton fibres, as described, and impregnated with a rubber-containing compound, the proportion of relatively longer fibres being greater than the proportion of the relatively shorter cotton fibres, and the shorter fibres being thin and substantially individually isolated, and at least a portion of the longer fibres being relatively thick, unravelled bundles of fibres.

5. A leather-like material comprising in ad- 'mixture, relatively long and short fibres, as described, and rubber-containing compound, a portion of the fibres being of vegetable origin, and the proportion of relatively longer fibres being greater than that of the relatively shorter fibres,

and the shorter fibres being thin and substantially individually isolated, and at least a portion of the longer fibres being relatively thick, unravelled bundles of fibres.

6. A water-laid felt consisting of a mixture of relatively long and short fibres, as described, a portion of the fibres being of vegetable origin, and the proportion of relatively longer fibres being greater than that of the relatively shorter fibres, and the shorter fibres being thin and substantially individually isolated, and at least a portion of the longer fibres being relatively thick, unravelled bundles of fibres. g y

'7. A water-laid fibrous product consisting of a mixture of relatively long and short cotton fibres, as described, the proportion of relatively longer cotton fibres being greater than that of the relatively shorter cotton fibres, and the shorter fibres being thin and substantially individually isolated,

and at least a portion of the longer fibres being relatively thick, unravelled bundles of fibres.

8. A water-laid, absorbent, fibrous product consisting of a mixture of relatively long and short cotton fibres, as described, the proportion of the relatively longer cotton fibres being greater than that of the relatively shorter cotton fibres, the relatively shorter fibre being distributed in felted relation throughout the relatively longer cotton fibre, and the shorter fibres being thin and substantially individually isolated, and at least a portion of the longer fibres being'relatively thick, unravelled bundles of fibres.

9. A water-laid fibrous product consisting of a mixture of relatively long and short fibres, as described, a portion of the fibres being of vegetable origin, and the proportion of relatively longer fibres being greaterthan that of the relatively shorter fibres, the shorter fibres being thin,

of fibres.

HENRY PHILIP SHOPNECK 

